%{

int scans = 0;
int prints = 0;
%}

%%
scanf {
    scans++;
    fprintf(yyout, "readf");
};
printf {
    prints++;
    fprintf(yyout, "writef"); 
}
. fprintf(yyout, "%s", yytext);
\n fprintf(yyout, "\n");
%%

int main(void) {
    yyin=fopen("4/input", "r+");
    yyout=fopen("4/output", "w");
    yylex();
    printf("%d printf occurrence(s)\n", prints);
    printf("%d scanf  occurrence(s)\n", scans);
}

int yywrap()
{
    return(1);
}