A_2020_2

#include <stdio.h>
#include <stdlib.h>

int main()
{
    FILE* f=fopen("input_1.txt","r");
    if(!f)
        return -1;
    char c1, c2;
    char*s=calloc(1e6,sizeof(char));
    int k=0;
    while(!feof(f))
    {
        fscanf(f,"%c",&s[k++]);
    }
    realloc(s,(k+1)*sizeof(char));
    int l=strlen(s);
    for(int i=0; i<l; i++)
        if(s[i]=='a')
        {
            if(s[i+1]<='9'&&s[i+1]>='1')
            {
                int k=s[i+1]-'1'+1;
                int j=i+2;
                while(s[j]<='9'&&s[j]>='1')
                    k=k*10+s[j++]-'1'+1;
                if((k>='a'&&k<='z')||(k>='A'&&k<='Z'))
                    printf("%c",k);
                    i=j-1;
            }
            else printf("%c",'a');
        }
        else if((s[i]<='Z'&&s[i]>='A')||(s[i]<='z'&&s[i]>='a')) printf("%c",s[i]);

    return 0;
}