#include
using namespace std;
string keys []={"",“abc”,“def”,“ghi”,“jkl”,“mno”,“pqrs”,“tuv”,“wxyz”};
void phone(char* input,int i,char* output,int j){
//base case
if(input[i]==’\0’){
output[j]=’\0’;
cout<<output<<" ";
return;
}
//recursive case
int digit=input[i]-‘0’;
for(int k=0;keys[digit][k]!=’\0’;k++){
output[j]=keys[digit][k];
phone(input,i+1,output,j+1);
}
}
int main() {
char input[100];
cin>>input;
char output[100];
phone(input,0,output,0);
}