#include <cstdio>
#include <cstdint>

constexpr intmax_t FRAC_MAX = 10000000000;

int main() {
  int N;
  scanf("%d", &N);

  intmax_t intpart = 0;
  intmax_t fracpart = 0;
  for (int i = 0; i < N; ++i) {
    char A[32];
    scanf("%s", A);

    const char* p = A;
    bool neg = (*p == '-');
    if (neg) ++p;

    intmax_t ip = *p-'0';
    intmax_t fp = 0;
    while (*++p >= '0')
      ip = ip*10 + *p-'0';

    if (*p == '.') {
      ++p;
      fp = *p-'0';
      int digno = 1;
      while (*++p >= '0') {
        fp = fp*10 + *p-'0';
        ++digno;
      }
      while (digno++ < 10) fp *= 10;
    }

    if (neg) {
      ip = -ip;
      fp = -fp;
    }

    intpart += ip;
    fracpart += fp;

    if (fracpart >= FRAC_MAX) {
      ++intpart;
      fracpart -= FRAC_MAX;
    } else if (fracpart < 0) {
      --intpart;
      fracpart += FRAC_MAX;
    }
  }

  if (intpart < 0 && fracpart > 0) {
    ++intpart;
    if (intpart == 0) putchar('-');
    fracpart = FRAC_MAX - fracpart;
  }
  printf("%jd.%010jd\n", intpart, fracpart);
}