%{
#include <stdio.h>

int line = 0; 
%}

%%
[\n] {line++;}
. {}
             
%%

int yywrap{}
{
   return 1;
}
int main()
{
  extern FILE *yyin,*yyout
  yyin=fopen("input.txt","r")//to read 
  yyin=fopen("output.txt","w") //to write 
  yylex();
  fprint(yyout,"no of lines=%d\n",line);
  return 0;
}