how many canals are longer than thirty miles?
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col : canal | length (miles) | locks | max length (ft) | width (ft) | year opened | year abandoned | year restored row 1 : aberdeenshire canal | 18 | 18 |  |  | 1805 | 1854 |  row 2 : buchan canal |  |  |  |  |  |  |  row 3 : caledonian canal | 62 | 29 | 150 | 35 | 1822 |  |  row 4 : crinan canal | 9 | 15 | 86.75 | 19.65 | 1817 |  |  row 5 : dingwall canal | 1.1 | 0 |  |  | 1816 | 1840 |  row 6 : forth and clyde canal | 35 | 38 | 68.58 | 19.75 | 1790 | 1963 | 2002 row 7 : glasgow, paisley and johnstone canal | 11 | 0 |  |  | 1811 | 1881 |  row 8 : monkland canal | 12.25 | 18 | 71 | 14 | 1794 | 1942 |  row 9 : stevenston canal | 2.25 | 0 |  | 13 | 1772 | 1830 |  row 10 : union canal | 31.5 | 3 | 63 | 12.5 | 1822 | 1930 | 2000
how many canals are longer than thirty miles?
Canal Length (miles) Locks Max length (ft) Width (ft) Year opened Year abandoned Year restored
Aberdeenshire Canal 18 18 1805 1854
Buchan Canal
Caledonian Canal 62 29 150 35 1822
Crinan Canal 9 15 86.75 19.65 1817
Dingwall Canal 1.1 0 1816 1840
Forth and Clyde Canal 35 38 68.58 19.75 1790 1963 2002
Glasgow, Paisley and Johnstone Canal 11 0 1811 1881
Monkland Canal 12.25 18 71 14 1794 1942
Stevenston Canal 2.25 0 13 1772 1830
Union Canal 31.5 3 63 12.5 1822 1930 2000
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