#include <stdio.h>

int main(void) {
    int n = 100;
    int count = 0;
    int i, j, is_prime;
    for (i=n; i>=2; i--) {
        is_prime = 1;
        for (j=2; j<i; j++){
            if(i%j == 0) {
                is_prime = 0;
                break;
            }
        }
        if(is_prime == 1) count++;
    }
    printf("%d以下の素数は%d個ある\n", n, count);
    return 0;
}