#include <time.h>
#include <stdlib.h>
#include <stdio.h>



int rand7(void)
{
    const int ret[][2] = {
        {2, 1}, {3, 2}, {5, 3}, {6, 4}, {8, 5}, {10, 6}, {12, 7}
    };
    srand((unsigned)time(NULL));
    int a = rand() % 5 + 1;
    int b = rand() % 5 + 1;
    int i;
    for (i = 0; i < 7; i++) {
        if (a*b == ret[i][0]) {
            return ret[i][1];
        }
    }
    return 0;    
}

int main(void)
{
    int num = 0;
    while (num == 0) {
        num = rand7();
    }
    printf("%d\n", num);
    return 0;
    
}