#include <bits/stdc++.h>
using namespace std;
void fastIO() {
  std::ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
}
template <typename T, typename U>
inline void mnze(T &x, U y) {
  if (y < x) x = y;
}
template <typename T, typename U>
inline void mxze(T &x, U y) {
  if (x < y) x = y;
}
void _scan(int &x) { scanf("%d", &x); }
void _scan(long long &x) { scanf("%lld", &x); }
void _scan(double &x) { scanf("%lf", &x); }
void _scan(char &x) { scanf(" %c", &x); }
void _scan(char *x) { scanf("%s", x); }
void scan() {}
template <typename T, typename... U>
void scan(T &head, U &...tail) {
  _scan(head);
  scan(tail...);
}
template <typename T>
void _dbg(const char *sdbg, T h) {
  cerr << sdbg << "=" << h << "\n";
}
template <typename T, typename... U>
void _dbg(const char *sdbg, T h, U... t) {
  while (*sdbg != ',') cerr << *sdbg++;
  cerr << "=" << h << ",";
  _dbg(sdbg + 1, t...);
}
long long a, b;
bool prime(long long x) {
  long long d = 2;
  while (d * d <= x) {
    if (x % d == 0) return false;
    d++;
  }
  return true;
}
int main() {
  int t;
  scan(t);
  while (t--) {
    scan(b, a);
    if (b - a != 1) {
      printf("NO\n");
    } else {
      if (prime(b + a))
        printf("YES\n");
      else
        printf("NO\n");
    }
  }
}
