#include <iostream>
#include <vector>
#include <set>
#include <algorithm>

#define rep(i,a) for(int i = 0 ; i < a ; i ++)
#define loop(i,a,b) for(int i = a ; i < b ; i ++)
#define vi vector<int>
#define vs vector<string>
#define pii pair<int, int>
#define f first
#define s second
#define pb push_back
using namespace std;

int main(void){
  int a,b;
  string s;
  cin>>a>>b>>s;
  bool f = true;
  rep(i,s){
    if(i != a){
      if('0' <= a[i] && a[i] <= '9');
      else f = false;
    }else{
      if('-' != a[i])f = false;
    }
  }
  cout<<(f?"Yes":"No")<<endl;
}