#include <bits/stdc++.h>
using namespace std;
const long double PI = acos(-1.0);
const long long MAX = 9000000000000000000;
const long long MIN = -9000000000000000000;
const long double DMAX = 4500;
const long double DMIN = -4500;
const long long MOD = 1000000007;
void Main() {
  long long a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  for (long long i = 0; i < a + b + 1; i++) {
    if (i != a && s[i] <= '9' && s[i] >= '0') {
      continue;
    } else {
      cout << ("No") << endl;
      return;
    }
    if (i == a && s[i] != '-') {
      cout << ("No") << endl;
      return;
    }
  }
  cout << ("Yes") << endl;
}
int main() {
  cout << fixed << setprecision(20);
  Main();
  return 0;
}
