#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) {
  long long temp;
  while (b > 0) {
    temp = a % b;
    a = b;
    b = temp;
  }
  return a;
}
long long lcm(long long a, long long b) { return a * b / gcd(a, b); }
long long fpow(long long b, long long exp, long long mod) {
  if (exp == 0) return 1;
  long long t = fpow(b, exp / 2, mod);
  if (exp & 1) return t * t % mod * b % mod;
  return t * t % mod;
}
long long divmod(long long i, long long j, long long mod) {
  i %= mod, j %= mod;
  return i * fpow(j, mod - 2, mod) % mod;
}
clock_t time_p = clock();
void TimeTaken() {
  time_p = clock() - time_p;
  cerr << "Completion time : " << (float)(time_p) / CLOCKS_PER_SEC << "\n";
}
void solve() {}
int main() {
  int a, b, flag = 0;
  cin >> a >> b;
  string s;
  cin >> s;
  for (int i = int(a + 1); i <= int(a + b); i++) {
    if (isdigit(s[i]) && s[a] == '-')
      flag = 0;
    else {
      flag = 1;
      break;
    }
  }
  if (flag == 0)
    cout << "Yes";
  else
    cout << "No";
  return 0;
}
