#include <bits/stdc++.h>
using namespace std;
const int N = 1e7 + 4;
void FastInputOutput() {
  ios_base ::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
}
inline long long LLD() {
  long long ret;
  scanf("%lld", &ret);
  return ret;
}
inline int D() {
  int ret;
  scanf("%d", &ret);
  return ret;
}
void bin(int x) {
  if (!x) return;
  bin(x / 2);
  cout << x % 2;
}
bool checkPrimeNumber(int n) {
  bool flag = true;
  for (int j = 2; j <= n; ++j) {
    if (n % j == 0) {
      flag = false;
      break;
    }
  }
  return flag;
}
bool cmp(string last, string first) {
  if (last.size() < first.size()) return 1;
  return 0;
}
int calculateDigit(int n) {
  double temp = (double)(n);
  double a = 0.39908 - (0.434294 * n);
  double b = log10(n);
  double c = (n + 0.5) * b;
  double ans = c - abs(a);
  return ceil(ans);
}
int findDigits(int n) {
  double E = 2.71828182845904523536;
  double PI = 3.141592654;
  if (n < 0) return 0;
  if (n <= 1) return 1;
  double x = ((n * log10(n / E) + log10(2.0 * PI * n) / 2.0));
  return floor(x) + 1;
}
long long fact(long long n) {
  long long ans = 1;
  for (long long i = 1; i <= n; ++i) ans *= i;
  return ans;
}
unsigned long long Factorial(int n) {
  const unsigned int M = 1000000007;
  unsigned long long f = 1;
  for (int i = 1; i <= n; i++) f = (f * i) % M;
  return f;
}
int main() {
  FastInputOutput();
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  int flag = 0;
  if (s[a] == '-') {
    flag = 1;
    for (int i = a + 1; i <= a + b; ++i) {
      if ((int)(s[i] - 48) >= 0 && (int)(s[i] - 48) <= 9) {
      } else {
        flag = 0;
        break;
      }
    }
  }
  if (flag)
    cout << "Yes"
         << "\n";
  else
    cout << "No"
         << "\n";
}
