int main(){
    int m,t,s,n,h;
    scanf("%d %d %d",&m,&t,&s);
    if(s*m<=t||t==0){
        printf("0");
    }else{
    h=s%t;
    if(h==0){h=s/t;
        n=m-h;
        printf("%d",n);
    }else{
        h=s/t+1;
        n=m-h;
        printf("%d",n);
    };}
    return 0;
}bhrh