#include<iostream> #include<cstdio> #include<math.h> using namespace std; int prime(int x); int main() { int a, b; while(scanf("%d %d", &a, &b) != EOF) { long long sum = 0; if(a > b) { int tmp = a; a = b; b = tmp; } for(int i = a + 1; i < b; i++) if(prime(i)) sum += i; cout << sum << endl; } return 0; } int prime(int x) { int flag = 1; for(int i = 2; i <= sqrt(x); i++) if(x % i == 0) { flag = 0; break; } return flag; } |
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