Codeforces Round 166 (Div. 2)
B
Prime Matrix
Codeforces
1300
原题
← AC →
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You've got an $*n* × *m*$ matrix. The matrix consists of integers. In one move, you can apply a single transformation to the matrix: choose an arbitrary element of the matrix and increase it by $1$. Each element can be increased an arbitrary number of times.

翻译中…

You are really curious about prime numbers. Let us remind you that a prime number is a positive integer that has exactly two distinct positive integer divisors: itself and number one. For example, numbers 2, 3, 5 are prime and numbers 1, 4, 6 are not.

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A matrix is prime if at least one of the two following conditions fulfills:

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  • the matrix has a row with prime numbers only;
  • the matrix has a column with prime numbers only;
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Your task is to count the minimum number of moves needed to get a prime matrix from the one you've got.

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Input

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The first line contains two integers $*n*, *m*$ $(1 ≤ *n*, *m* ≤ 500)$ — the number of rows and columns in the matrix, correspondingly.

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Each of the following $*n*$ lines contains $*m*$ integers — the initial matrix. All matrix elements are positive integers. All numbers in the initial matrix do not exceed $10^{5}$.

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The numbers in the lines are separated by single spaces.

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Output

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Print a single integer — the minimum number of moves needed to get a prime matrix from the one you've got. If you've got a prime matrix, print 0.

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Note

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In the first sample you need to increase number 1 in cell (1, 1). Thus, the first row will consist of prime numbers: 2, 2, 3.

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In the second sample you need to increase number 8 in cell (1, 2) three times. Thus, the second column will consist of prime numbers: 11, 2.

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In the third sample you don't have to do anything as the second column already consists of prime numbers: 3, 2.

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样例

Input #1
3 3
1 2 3
5 6 1
4 4 1
Output #1
1
InputCopy OutputCopy
Input #2
2 3
4 8 8
9 2 9
Output #2
3
InputCopy OutputCopy
Input #3
2 2
1 3
4 2
Output #3
0
InputCopy OutputCopy
题目信息
题号
271B
时间限制
2 s
内存限制
256 MB
标签
二分
暴力
数学
数论

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