#include //Written by Coffee. 判断素数 int isPrime(int num) { if (num == 2 || num == 3) { return 1; } if (num % 6 != 1 && num % 6 != 5) { return 0; } for (int i = 5; i*i <= num; i += 6) { if (num % i == 0 || num % (i+2) == 0) { return 0; } } return 1; } int main() { int a; scanf("%d",&a); for(int i=2;i<=a/2;i++) { if(isPrime(i)&&isPrime(a-i)) { printf("%d=%d+%d\n",a,i,a-i); } } return 0; }