#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

#define rd_init() char*rp=({char*mmap();mmap(0l,1l<<25,1,2,0,0ll);})
#define rd() ({int _v=0,_c;while(_c=*rp++-48,_c>=0)_v=_v*10+_c;_v;})
#define wt(v) ({ulong _z=v;do*--wp=_z%10+48;while(_z/=10);})
#define repeat(e) for(typeof(e)_=e;_--;)

typedef unsigned long ulong;

int main(){
	rd_init();
	int n=rd();
	long s=0;
	repeat(n){
		if(*rp=='-'){
			++rp;
			s-=rd();
		}else{
			s+=rd();
		}
	}
	
	char wbuf[64],*wp=wbuf+sizeof wbuf;
	if(s<0){
		ulong v=-s;
		wt(v);
		*--wp='-';
	}else{
		ulong v=s;
		wt(v);
	}
	write(1,wp,wbuf+sizeof wbuf-wp);
	_exit(0);
}