include <stdio.h>

include <stdlib.h>

int f(const void * x,

const void * y) {
return * (int * ) x - * (int * ) y;

}

int main() {

int n, m, i, t, k = 0, d = 0;
static int a[256], b[256], v[256];

if (scanf("%d%d", & n, & m) != 2) return 0;

for (i = 0; i < n; i++) {
    if (scanf("%d", & t) == 1) a[t]++;
}
for (i = 0; i < m; i++) {
    if (scanf("%d", & t) == 1) b[t]++;
}

for (i = 0; i < 256; i++) {
    if (a[i] || b[i]) {
        v[k++] = a[i] + b[i];
    }
}

qsort(v, k, sizeof(int), f);

for (i = 0; i < k; i++) {
    if (m >= v[i]) {
        m -= v[i];
        d++;
    } else {
        break;
    }
}

printf("%d", k - d);

return 0;

}