#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int A, B;
  string S;
  cin >> A >> B >> S;
  int flag;
  for (int i = 0; i <= A + B; i++) {
    if ((i == A && S.at(i) != '-') || (i != A && S.at(i) == '-')) {
      flag = 1;
      break;
    }
  }
  if (flag == 1) {
    cout << "No" << endl;
  } else {
    cout << "Yes" << endl;
  }
}
