#pragma GCC optimize("O3", "unroll-loops")
#include<ios>
char s[100<<20],answer[100<<20];
inline void removespace(char* answer,char const* string,size_t size){
    for(size_t i=0;i<size;){
        if(string[i]!=' '){
            *answer++ = string[i];
            ++i;
        }else{
            uint_fast64_t n=0;
            do{
                ++n;
                ++i;
            }while(string[i]==' ');
            if(n&1)*answer++ = ' ';
        }
        *answer=0;
    }
}
int main(){
        fread_unlocked(s,1,100<<20,stdin);
        removespace(answer,s,100<<20);
    fputs_unlocked(answer,stdout);
}