10921-Find The Telephone

#include<stdio.h>
#include<string.h>
int main ()
{
    char a;
    while(scanf("%c",&a)==1){
            if(a=='A' || a=='B'|| a=='C')
                printf("2");
            else if(a=='D' || a=='E'|| a=='F')
                printf("3");
            else if(a=='G' || a=='H'|| a=='I')
                printf("4");
            else if(a=='J' || a=='K'|| a=='L')
                printf("5");
            else if(a=='M' || a=='N'|| a=='O')
                printf("6");
            else if(a=='P' || a=='Q'|| a=='R' || a=='S')
                printf("7");
            else if(a=='T' || a=='U'|| a=='V')
                printf("8");
            else if(a=='W' || a=='X'|| a=='Y' || a=='Z')
                printf("9");
            else if (a=='1')
                printf("1");
            else
                printf("%c",a);

        }
         return 0;
    }