#include <stdio.h>

#define MAXNUM 10002

int main() {

    int m, n;

    int cost[MAXNUM];    // the Cost for every school

    float prob[MAXNUM];  // the probality for every school

    float probs[MAXNUM]; // the probality for All-amount-money

    int i, j;

    while ( scanf("%d %d", &n, &m)!=EOF && (m||n)) {

        for (i=; i<m; ++i) {

            scanf("%d %f", &cost[i], &prob[i]);

            prob[i] = 1.0f - prob[i];

        }

        for (i=; i<=n; i++)

            probs[i] = 1.0f;

        for (i=; i<m; ++i) {

            for (j=n; j>=cost[i]; --j) {

                if (probs[j-cost[i]] * prob[i] < probs[j])

                    probs[j] = probs[j-cost[i]] * prob[i];

            }

        }

        printf("%.1f%%\n", (1.0f-probs[n])*100.0f);

    }

    return ;

}