#include<string.h>
#include<ctype.h>
#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>

#define BUFSIZE 4096
#define MARGIN 50

int main(){
	char buffer[BUFSIZE]; 
	char extra_buffer[BUFSIZE-MARGIN];
	size_t readlen = read(0, buffer, BUFSIZE);
	size_t number_end = 0, number_beginning = 0;
	double sum = 0;
	while(number_end < readlen){
		for(; number_end < readlen && !isspace(buffer[number_end]); number_end++);
		buffer[number_end] = 0; 
		sum += atof(buffer + number_beginning);
		for(number_beginning = number_end + 1; isspace(buffer[number_beginning]); number_beginning++);
		number_end = number_beginning;
		if(number_end > readlen - MARGIN){ // do we need to refill the buffer?
			size_t extra_readlen = read(0, extra_buffer, BUFSIZE-MARGIN);
			if(!extra_readlen)
				continue;
			strncpy(buffer, buffer+number_end, readlen - number_end);
			strncpy(buffer + (readlen - number_end), extra_buffer, extra_readlen);
			readlen = (readlen - number_end) + extra_readlen;
			number_beginning = number_end = 0;
		}
	}
	printf("%lf\n", sum);
	return 0;
}