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def main():
    import sys
    data = sys.stdin.read().strip().split()
    if not data:
        return
    n = int(data[0])
    m = int(data[1])
    s = int(data[2])
    intervals = []
    pos = 3
    for _ in range(m):
        l = int(data[pos])
        r = int(data[pos + 1])
        pos += 2
        intervals.append((l, r))
    intervals.sort(key=lambda x: x[0])
    free_intervals = []
    if intervals[0][0] > 1:
        free_intervals.append((1, intervals[0][0] - 1))
    for i in range(len(intervals) - 1):
        if intervals[i][1] + 1 < intervals[i + 1][0]:
            free_intervals.append((intervals[i][1] + 1, intervals[i + 1][0] - 1))
    if intervals[-1][1] < n:
        free_intervals.append((intervals[-1][1] + 1, n))
    best = None
    best_distance = None
    for a, b in free_intervals:
        if s < a:
            candidate = a
            dist = a - s
        elif s > b:
            candidate = b
            dist = s - b
        else:
            candidate = s
            dist = 0
        if best_distance is None or dist < best_distance or (dist == best_distance and candidate < best):
            best_distance = dist
            best = candidate
    sys.stdout.write(str(best))

if __name__ == '__main__':
    main()