#include <bits/stdc++.h>
using namespace std;
const int INTINF = 1 << 29;
const long long LLINF = 1LL << 61;
const int MOD = (int)1e9 + 7;
const double EPS = 1e-9;
const int DX[8] = {0, 1, 0, -1, 1, 1, -1, -1};
const int DY[8] = {1, 0, -1, 0, 1, -1, 1, -1};
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int a, b;
  cin >> a >> b;
  string S;
  cin >> S;
  bool ans = true;
  for (int i = (0); i < (a + b + 1); ++i) {
    if (i == (b - 1)) {
      if (S[i] != '-') ans = false;
    } else {
      if (S[i] == '-') ans = false;
    }
  }
  if (ans)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
