void printFile(FILE *fout,int grid[][1024],int rows,int cols, int grayscale){
    int i,j;
    fprintf(fout,"P2\n");
    fprintf(fout,"%d %d\n", rows, cols);
    fprintf(fout,"%d\n", grayscale);
    for(i=0;i<rows;i++){
        for(j=0;j<cols;j++){
            fprintf(fout,"%d ", grid[i][j]);
        }
        fprintf(fout,"\n");
    }
}