#include<bits/stdc++.h>
using namespace std;
char keypad[][10]={"","",“ABC”,“DEF”,“GHI”,“JKL”,“MNO”,“PQRS”,“TUV”,“WXYZ”};
void phone_keypad(char in[],char out[],int i,int j){
if(in[i]==’\0’){
out[j]='\0';
cout<<out<<endl;
return;
}
//recursive calls
//1. just break one part and apply recursions
//2.consider case for when in[i]= null character
int digit = in[i] - ‘\0’;
if(digit==1 || digit==0){
phone_keypad(in,out,i+1,j); //case wen null character is strikened
}
for(int k=0;keypad[digit][k]!='\0';k++){
out[j]=keypad[digit][k]; // [ a_ _ ,b_ _,c_ _ ]
phone_keypad(in,out,i+1,j+1);
}
}
int main(){
char in[100];
cin>>in;
char out[100];
phone_keypad(in,out,0,0);
return 0;
}