#include<stdio.h>
#include<string.h>
#define length 100
int a[length + 1], b[length + 1], diff[length + 1];
void add(int a[], int b[], int sum[])
{
    memset(sum, 0, length);
    int i, j, k;

    for (i = length; a[i] == 0 && i >= 0; --i);

    for (j = length; b[j] == 0 && j >= 0; --j);

    int max = i > j ? i : j;

    for (k = 0; k <= max; ++k) {
        int tmp = a[k] + b[k];

        if (tmp > 10) {
            sum[k + 1] = tmp / 10;
            sum[k] = tmp % 10;
        } else sum[k] = tmp;
    }
}
int noLessThan(int a[], int b[])
{
    int i, j;

    for (i = length; a[i] == 0 && i >= 0; --i);

    for (j = length; b[j] == 0 && j >= 0; --j);

    if (i < j) return 0;
    else if (i == j) {
        while (i >= 0 && a[i] >= b[i])--i;

        if (i < 0) return 0;
    }

    return 1;
}
void jiewei(int a[])
{
    int i;

    for (i = length; a[i] == 0 && i >= 0; --i);

    for (int j = 0; j <= i; ++j)
        if (a[j] < 0) {
            a[j] += 10;
            a[j + 1] -= 1;
        }
}
void sub(int a[], int b[], int diff[])
{
    int i, j, k;

    for (i = length; a[i] == 0 && i >= 0; --i);

    for (j = length; b[j] == 0 && j >= 0; --j);

    for (k = 0; k <= i; ++k)
        diff[k] = a[k] - b[k];

    jiewei(diff);
}
void getData(int p[])
{
    char c[length + 1];
    int i, k;
    gets(c);

    for (k = 0, i = strlen(c) - 1; i >= 0; ++k, --i)
        p[k] = c[i] - '0';
}
void print(int p[], int maxLength)
{
    int i;

    for (i = maxLength; p[i] == 0 && i >= 0; --i);

    for (int j = i; j >= 0; --j)   printf("%d", p[j]);

    if (p[i] == 0)printf("0");

    printf("\n");
}
int main(void)
{
    getData(a);
    getData(b);

    if (noLessThan(a, b))
        sub(a, b, diff);
    else {
        int i;
        sub(b, a, diff);

        for (i = length; i >= 0 && diff[i] == 0; --i);

        diff[i] = -diff[i];
    }

    print(diff, length);
    return 0;
}