#include <bits/stdc++.h>
using namespace std;
const double EPS = 1e-10;
const double PI = acos(-1.0);
int main() {
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  int f = 1;
  for (int i = 0; i < a + b + 1; ++i) {
    if (i == a) {
      if (s[i] == '-') f = 0;
    } else {
      if (s[i] < '0' || s[i] > '9') f = 0;
    }
  }
  if (f)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
