#include <bits/stdc++.h>
using namespace std;
const long long INF = 1e18 + 10;
const long long MINF = -(1e18 + 10);
int main() {
  int a, b, cnt = 0;
  string ss;
  cin >> a >> b >> ss;
  int n = (int)ss.size();
  if (ss[a + 1] != '-') {
    cout << "No" << endl;
    return 0;
  }
  for (int i = 0; i < n; i++) {
    if (ss[i] >= '0' && ss[i] <= '9') cnt++;
  }
  if (cnt == a + b)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
