#include <algorithm>
#include <cstdint>
#include <iostream>

int main() {
    int32_t n, x, m;
    std::cin >> n >> x >> m;
    --x;
    int32_t clockwise = 0;
    for (int32_t i = 0; i < m; ++i) {
        int32_t v;
        std::cin >> v;
        --v;
        clockwise += v < x;
    }

    int32_t ans = std::min(clockwise, m - clockwise);

    std::cout << ans << '\n';

    return 0;
}