#include<bits/stdc++.h>
using namespace std;
 
#define pfi(a) printf("%d",a);
#define pfl(a) printf("%lld",a);
#define pfin(a) printf("%d\n",a);
#define pfln(a) printf("%lld\n",a);
#define pfis(a) printf("%d ",a);
#define pfls(a) printf("%lld ",a);
#define sfi(a) scanf("%d",&a);
#define sfl(a) scanf("%lld",&a);
#define fast ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define f(i,a,b) for(int i=a;i<b;i++)
#define pb(a) push_back(a);
#define mp(a,b) make_pair(a,b)
#define ll long long   

const ll mod=1e9+7;

int main()
{
  string s;
  ll a,b;
  sfl(a);
  sfl(b);
  cin>>s;
  i=0;
  ll flag=0;
  while(s[i]!='\0')
  {
    if(s[i]=='-' || s[i]=='0'||s[i]=='1'||s[i]=='2'||s[i]=='3'||s[i]=='4'||s[i]=='5'||s[i]=='6'||s[i]=='7'||s[i]=='8'||s[i]=='9')
    {
      flag=1;
    }
    else
    {
      flag=0;
      break;
    }
  }
  if(flag==1 && s[a]=="-")
  {
    
    cout<<"Yes"<<endl;
  }
  else
  {
    cout<<"No"<<endl;
  }
return 0;
}