cf/628/C

#include <cstdio>
char a[100010];
int main(){
    int n,k;
    scanf("%d %d",&n,&k);
    scanf("%s",a);
    int sum=k;
    for(int i=0;i<n;i++){
        if(a[i]-‘a‘>‘z‘-a[i]){
            if(sum<=a[i]-‘a‘){
                a[i]=a[i]-sum;
                sum=0;
                break;
            }else{
                sum-=(a[i]-‘a‘);
                a[i]=‘a‘;
            }
        }else{
            if(sum<=‘z‘-a[i]){
                a[i]=a[i]+sum;
                sum=0;
                break;
            }else{
                sum-=(‘z‘-a[i]);
                a[i]=‘z‘;
            }
        }
    }
    if(sum){
        printf("-1");
    }else{
        printf("%s",a);
    }
    scanf("%d %d",&n,&k);
    return 0;
}