#include <iostream>
#include <math.h>
#include <algorithm>
#include <vector>
#include <numeric>
#include <string>
using namespace std;
const double PI = acos(-1.0);
const string alp = "abcdefghijklmnopqrstuvwxyz";
const string ALP = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define REP1(i,n) FOR(i,1,n+1)
#define SUM(c) accumulate((c).begin(),(c).end(),0)
#define UNIQ(c) (c).erase(unique((c).begin(), (c).end()), (c).end());
#define Yn(b) puts(b?"Yes":"No")
#define YN(b) puts(b?"YES":"NO")
 
bool isprime(int p) {
  if (p==1) return false;
  FOR(i,2,p) {
    if (p%i==0) return false;
  }
  return true;
}
 
int main(){
  int a,b:
  string s;
  cin >> a >> b >> s;
  REP(i,s.length()){
    if(i==a+1) {
      if (s[i]!="-") {
        puts("No");
        return 0;
      }
    } else {
      if (s[i]=="-") {
        puts("No");
        return 0;
      }
    }
  }
  puts("Yes");
  return 0;
}