include <stdio.h>
using namespace std;
int A, B;
char S[12];
bool correct = true;
int main() {
  scanf("%d %d", &A, &B);
  scanf("%s", S);
  int i = 0;
  while (i < A) {
    if (S[i] == '-') {
      correct = false;
    }
    i++;
  }
  if (S[i] != '-') {
    correct = false;
  }
  i++;
  while (i < A+B) {
    if (S[i] == '-') {
      correct = false;
    }
    i++;
  }
  if (correct) {
    printf("Yes\n");
  } else {
    printf("No\n");
  }
  return 0;
}
