#include<stdio.h> #include<stdlib.h> #include<string.h> #include<math.h> #include<ctype.h> int main() { int i, j, n, flag; int h1, m1, h2, m2; int sum1, sum2, temp; int x, y, z; while (scanf("%d:%d",&h1,&m1)!=EOF) { scanf("%d:%d", &h2, &m2); sum1 = h1 * 60 + m1; sum2 = h2 * 60 + m2; if (sum1 > sum2) { temp = sum1; sum1 = sum2; sum2 = temp; } n = 0; for (i = sum1; i <= sum2; i++) { flag = 0; x = i / 60; y = i % 60; z = x * 2500 + y; for (j = 2; j*j <= z; j++) { if (z%j == 0) { flag = 1; break; } } if (flag == 0) n++; } printf("%d\n", n); } return 0; } |
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