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#include <inttypes.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#define N 1000
#define isnum(c) (c == '-' || (c >= '0' && c <= '9'))
int64_t readl(int64_t nums[], char *buf) {
int64_t i;
for (i = 0; *buf; buf++) {
if (!isnum(*buf)) continue;
nums[i++] = atoll(buf);
while (isnum(*buf)) buf++;
}
return i;
}
bool isconstant(int64_t a[], int n) {
for (int i = 0; i < n-1; i++)
if (a[i] != a[i+1])
return false;
return true;
}
int64_t next(int64_t a[], int64_t n) {
int64_t x = a[n-1];
if (isconstant(a, n))
return x;
for (int i = 0; i < n-1; i++)
a[i] = a[i+1] - a[i];
return x + next(a, n-1);
}
int main() {
char line[N];
int64_t s, a[N];
for (s = 0; fgets(line, N, stdin) != NULL; )
s += next(a, readl(a, line));
printf("%" PRId64 "\n", s);
return 0;
}
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