main(){
int c,l,b,f;
b=f=0;
l=-1;
c=getchar();
while(c!=-1){
if(c=='\n'){
b=f=0;
} else if(c=='#' && l=='#'){
f=1;
} else if(b==0 && f==0 && l=='#' && c==' '){
b=1;
} else if((b==1 || f==1) && l=='#' && c==' '){
f=0;b=0;
}
if(c=='#'){
putchar(c);
} else if(b==1){
putchar('.');
} else{
putchar(c);
}
l=c;
c=getchar();
}
}
Note that non-ascii characters in the above source code will be escaped (such as \x9f).