const input=require('fs').readFileSync('/dev/stdin','utf8').split(/[\s]/);const tn=():number=>{const a=input[0];input.shift();return Number(a)};const tnn=(n:number):number[]=>{const a=[];for(let i=0;i<n;i++){a.push(tn())}return a};const ts=():string=>{const a=input[0];input.shift();return String(a)};const tss=(n:number):string[]=>{const a=[];for(let i=0;i<n;i++){a.push(ts())}return a};const tc=():string=>{let a=input[0].split('');const b=a[0];a.shift();if(a.length>0){input[0]=a.join('')}else{input.shift()}return String(b)};const tcc=(n:number):string[]=>{const a=[];for(let i=0;i<n;i++){a.push(tc())}return a};const to=(...arg)=>{console.log(...arg)};const abs=(a)=>{return Math.abs(a)};const min=(...a)=>{return Math.min(...a)};const max=(...a)=>{return Math.max(...a)};const floor=(a)=>{return Math.floor(a)};const asc=(ar:number[])=>{return ar.sort((a,b)=>{return a-b})};const desc=(ar:number[])=>{return ar.sort((a,b)=>{return b-a})};const sw=(a,arr:any[],op:'=='|'>='|'>'|'<='|'<'='==')=>{for(let i=0;i<arr.length-1;i+=2){if(eval(a+op+arr[i])){return arr[i+1];}}return arr[arr.length-1]};const near=(n:number,arr:number[]):number=>{let ne=arr[0],ni=0;for(let i=1;i<arr.length;i++){if(Math.abs(n-ne)>Math.abs(n-arr[i])){ne=arr[i];ni=i}}return ni};const objvs =(a)=>{const b=[];for(const v in a){b.push(a[v])}return b};
const main=()=>{
  let [a,b]=tnn(2)
  let s=ts(),ans='Yes'
  for(let i=0;i<a;i++){
    if(!Number.isInteger(Number(s[i])))ans='No'
  }
  for(let i=a+1;i<a+b+1;i++){
    if(!Number.isInteger(Number(s[i])))ans='No'
  }
  to(ans)
}
main()
